Plug in Hybrid electric Vehicles Emit Nearly as Much as Petrol Cars, Study Finds

Plug-in hybrid cars release nearly five times greater global warming pollution than official data show, according to a recent report.

Growing Discrepancy Between Official and Actual Emissions

Data shows that PHEVs emit only one-fifth lower CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a non-profit organization. This differs sharply with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts examined data from in-vehicle energy use meters of eight hundred thousand vehicles registered in the EU between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, up from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported figures are decreasing,” stated a lead analyst participating in the report. “That discrepancy is growing and poses a significant problem. Consequently, PHEVs pollute nearly as much as petrol cars.”

Key Reasons Behind the Emissions Gap

Researchers linked the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric mode compared to overall mileage. The team found that only a quarter of driving was completed in EV mode, while lab assumptions suggested 84%.

Even, when running in electric mode, pollution levels were well above official projections. That happened because EV motors were insufficiently powerful enough to operate independently, resulting to engines using gasoline for nearly one-third of the distance completed in EV mode.

Policy and Financial Implications

Based on calculations, the lowballing of PHEV CO2 output enabled several major carmaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 more annually in running expenses than is estimated under laboratory conditions.

“The strong claims that automakers often promote about their plug-in hybrid vehicles are obviously way off the mark,” commented a transport expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little improved than regular gas and diesel cars in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Debate and Industry Lobbying

Hybrid cars have recently been drawn again into policy debates as carmakers have pressed the European Union to relax CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced intense lobbying from the car industry and opposition from EU countries with large automotive industries.

Some high-level politicians have proposed PHEVs as a potential “flexibility” solution to include in the regulation.

One independent energy economics specialist, who was not involved with the study, called the report a “highly valuable addition” after a long period in which parts of the car sector argued there was too little data to properly assess real-world CO2 output.

“The results demonstrate, beyond any doubt, that the difference in lab and real-world PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional cars,” they said. “All policy adjustments concerning PHEVs should be implemented with utmost caution and considering that evidence.”